overvaluation vs estimation

overvaluation and estimation both are nouns.

Word	Noun	Adjective	Verb	Adverb
overvaluation	Yes	No	No	No
estimation	Yes	No	No	No

As nouns, estimation is a hypernym of overvaluation; that is, estimation is a word with a broader meaning than overvaluation:

overvaluation: an appraisal that is too high
estimation: a document appraising the value of something (as for insurance or taxation)

Other hypernyms of overvaluation include appraisal, estimate.

overvaluation (noun)	estimation (noun)
too high a value or price assigned to something	a judgment of the qualities of something or somebody
an appraisal that is too high	an approximate calculation of quantity or degree or worth
	the respect with which a person is held
	a document appraising the value of something (as for insurance or taxation)